What are some ways to play outside of chord changes?
I know this isn't the most practical answer, but try to just follow your ear. Listen to people who play "outside", so you can get an idea in your ear of what you want the effect to be, and then just kind of jump off the deep end and go for it - the whole point is that you aren't matching up to the harmonies underneath you, so don't stress too hard about what notes you're playing!
Personally, I think you get the most effective sound by playing things that are tonal in isolation, or at least sound sort of tonal, but that clash with the underlying harmony. You could do something simple, like descending major triads, going up by whole steps:
A F# D B G# E C# A# F# Eb C Ab F D Bb ....
Then you can elaborate on that, say by playing a #4 up to the 5th of each triad:
(G# A F# D) (A# B G# E) (B# C# A# F#) (D Eb C Ab)
Then to really make it sound hip, it's cool to get your repetitive pattern in a rhythm so that it doesn't line up neatly with the beats. So you if play that sequence of notes in triplets, you get an effect like this (the top line is the meter, vertical lines are beats and dots are the subdivision).
| . . | . . | . . | . .
G# A F# D A# B G# E B# C# A# F#
See how the melodic grouping (#4 5 3 1) phases in and out with the rhythmic grouping (beats of three triplet notes)? Those kind of patterns are easy to construct and easy to practice, but they sound cool, and they give you a little more to hold onto than just random notes and rhythms.
One trick I've done is to play inside-outside-inside when doing a solo. Start in the changes and end in the changes, but have a little room in the middle to go crazy, particularly around dominant chords as someone has stated.
Here's some really common tricks:
- Side slipping: this is basically taking whatever scale you're playing and moving it up or down a semitone, then resolving back to an inside note. So for example playing in Db major over a C major chord.
- Implying different qualities of Dominant chords: For dominant chords you basically have 5 options for scales: Mixolydian, Diminished, Whole tone, Altered, and Lydian dominant. So if you're playing over a dominant chord you can use any or all of these scales, and because the nature of dominant chords is to provide dissonance that resolves to consonance, it'll sound great.
- Pentatonics: Pentatonic scales are very strong and good for implying alternate harmonies in your solos. You can go various degrees of outside the changes with these; say you're playing over Cmaj7. If you start playing using the D pentatonic scale it won't sound very out, A pentatonic will sound more out, and like Db or F# pentatonic will sound super out.
The most important thing when playing out is resolution. One note can make the difference between "He's playing random **** and it sounds bad" and "He's a jazz genius"
- Learn the notes that are inside.
- Don't play those notes